Which officer role requires serving at least one term as a Basileus of a graduate chapter to be eligible for election?

The role that requires serving at least one term as a Basileus of a graduate chapter to be eligible for election is the Regional Director. This requirement is significant as it ensures that candidates for this leadership position have firsthand experience and a deep understanding of the operations and dynamics within a graduate chapter. Serving as Basileus equips the individual with valuable skills in leadership, chapter management, and a strong grasp of the organization's values and mission, which are essential in guiding multiple chapters within a designated region.

The other roles mentioned might have different prerequisites that do not include this specific experience of having served as a Basileus. These requirements are designed to ensure that each officer brings appropriate qualifications and experiences to their role, contributing to the overall effectiveness of the organization's leadership structure.